An optical system incorporating a polarizer is used in solid-state imaging devices such as CCD and CMOS image sensors. The occasion of using the polarizer is increasing according to the necessity of separately handing light rays for the right eye and for the left eye particularly in an application of stereoscopic video (3D) used as a function in a video camera, a digital still camera, portable devices and so on. The polarizer in the solid-state imaging device is generally provided on the outside of an imaging device as a different component from the imaging device in a contact state or non-contact state of a polarizing filter.
As an inorganic polarizer, a wire grid polarizer (WGP) is proposed (for example, see JP-2002-328234 (Patent Document 1)). There are a reflection-type wire grid polarizer and an absorption-type wire grid polarizer as the wire grid polarizer. The reflection-type wire grid polarizer includes strip-shaped reflection layers formed in one dimensional grid state with a smaller pitch than a light wavelength band to be used. The absorption-type wire grid polarizer includes reflection layers made of strip-shaped thin films formed in one dimension grid state with a smaller pitch than the light wavelength band to be used, a dielectric layer formed on the reflection layers and an absorption layer formed on the dielectric layer.